Migrate 'lossy ptr2int cast' diagnostic

Author: clubby789

compiler/rustc_hir_typeck/messages.ftl

@@ -63,6 +63,11 @@ hir_typeck_lang_start_incorrect_param = parameter {$param_num} of the `start` la
 hir_typeck_lang_start_incorrect_ret_ty = the return type of the `start` lang item is incorrect
     .suggestion = change the type from `{$found_ty}` to `{$expected_ty}`
 
+hir_typeck_lossy_provenance_ptr2int =
+    under strict provenance it is considered bad style to cast pointer `{$expr_ty}` to integer `{$cast_ty}`
+    .suggestion = use `.addr()` to obtain the address of a pointer
+    .help = if you can't comply with strict provenance and need to expose the pointer provenance you can use `.expose_addr()` instead
+
 hir_typeck_method_call_on_unknown_raw_pointee =
     cannot call a method on a raw pointer with an unknown pointee type
 

compiler/rustc_hir_typeck/src/cast.rs

@@ -30,6 +30,7 @@
 
 use super::FnCtxt;
 
+use crate::errors;
 use crate::type_error_struct;
 use hir::ExprKind;
 use rustc_errors::{
@@ -1007,50 +1008,35 @@ impl<'a, 'tcx> CastCheck<'tcx> {
     }
 
     fn lossy_provenance_ptr2int_lint(&self, fcx: &FnCtxt<'a, 'tcx>, t_c: ty::cast::IntTy) {
-        fcx.tcx.struct_span_lint_hir(
+        let expr_prec = self.expr.precedence().order();
+        let needs_parens = expr_prec < rustc_ast::util::parser::PREC_POSTFIX;
+
+        let needs_cast = !matches!(t_c, ty::cast::IntTy::U(ty::UintTy::Usize));
+        let cast_span = self.expr_span.shrink_to_hi().to(self.cast_span);
+        let expr_ty = fcx.resolve_vars_if_possible(self.expr_ty);
+        let cast_ty = fcx.resolve_vars_if_possible(self.cast_ty);
+        let expr_span = self.expr_span.shrink_to_lo();
+        let sugg = match (needs_parens, needs_cast) {
+            (true, true) => errors::LossyProvenancePtr2IntSuggestion::NeedsParensCast {
+                expr_span,
+                cast_span,
+                cast_ty,
+            },
+            (true, false) => {
+                errors::LossyProvenancePtr2IntSuggestion::NeedsParens { expr_span, cast_span }
+            }
+            (false, true) => {
+                errors::LossyProvenancePtr2IntSuggestion::NeedsCast { cast_span, cast_ty }
+            }
+            (false, false) => errors::LossyProvenancePtr2IntSuggestion::Other { cast_span },
+        };
+
+        let lint = errors::LossyProvenancePtr2Int { expr_ty, cast_ty, sugg };
+        fcx.tcx.emit_spanned_lint(
             lint::builtin::LOSSY_PROVENANCE_CASTS,
             self.expr.hir_id,
             self.span,
-            DelayDm(|| format!(
-                    "under strict provenance it is considered bad style to cast pointer `{}` to integer `{}`",
-                    self.expr_ty, self.cast_ty
-                )),
-            |lint| {
-                let msg = "use `.addr()` to obtain the address of a pointer";
-
-                let expr_prec = self.expr.precedence().order();
-                let needs_parens = expr_prec < rustc_ast::util::parser::PREC_POSTFIX;
-
-                let scalar_cast = match t_c {
-                    ty::cast::IntTy::U(ty::UintTy::Usize) => String::new(),
-                    _ => format!(" as {}", self.cast_ty),
-                };
-
-                let cast_span = self.expr_span.shrink_to_hi().to(self.cast_span);
-
-                if needs_parens {
-                    let suggestions = vec![
-                        (self.expr_span.shrink_to_lo(), String::from("(")),
-                        (cast_span, format!(").addr(){scalar_cast}")),
-                    ];
-
-                    lint.multipart_suggestion(msg, suggestions, Applicability::MaybeIncorrect);
-                } else {
-                    lint.span_suggestion(
-                        cast_span,
-                        msg,
-                        format!(".addr(){scalar_cast}"),
-                        Applicability::MaybeIncorrect,
-                    );
-                }
-
-                lint.help(
-                    "if you can't comply with strict provenance and need to expose the pointer \
-                    provenance you can use `.expose_addr()` instead"
-                );
-
-                lint
-            },
+            lint,
         );
     }
 

compiler/rustc_hir_typeck/src/errors.rs

@@ -6,7 +6,7 @@ use rustc_errors::{
     AddToDiagnostic, Applicability, Diagnostic, DiagnosticArgValue, IntoDiagnosticArg, MultiSpan,
     SubdiagnosticMessage,
 };
-use rustc_macros::{Diagnostic, Subdiagnostic};
+use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::ty::Ty;
 use rustc_span::{
     edition::{Edition, LATEST_STABLE_EDITION},
@@ -231,6 +231,50 @@ pub struct LangStartIncorrectRetTy<'tcx> {
     pub found_ty: Ty<'tcx>,
 }
 
+#[derive(LintDiagnostic)]
+#[diag(hir_typeck_lossy_provenance_ptr2int)]
+#[help]
+pub struct LossyProvenancePtr2Int<'tcx> {
+    pub expr_ty: Ty<'tcx>,
+    pub cast_ty: Ty<'tcx>,
+    #[subdiagnostic]
+    pub sugg: LossyProvenancePtr2IntSuggestion<'tcx>,
+}
+
+#[derive(Subdiagnostic)]
+pub enum LossyProvenancePtr2IntSuggestion<'tcx> {
+    #[multipart_suggestion(hir_typeck_suggestion, applicability = "maybe-incorrect")]
+    NeedsParensCast {
+        #[suggestion_part(code = "(")]
+        expr_span: Span,
+        #[suggestion_part(code = ").addr() as {cast_ty}")]
+        cast_span: Span,
+        cast_ty: Ty<'tcx>,
+    },
+    #[multipart_suggestion(hir_typeck_suggestion, applicability = "maybe-incorrect")]
+    NeedsParens {
+        #[suggestion_part(code = "(")]
+        expr_span: Span,
+        #[suggestion_part(code = ").addr()")]
+        cast_span: Span,
+    },
+    #[suggestion(
+        hir_typeck_suggestion,
+        code = ".addr() as {cast_ty}",
+        applicability = "maybe-incorrect"
+    )]
+    NeedsCast {
+        #[primary_span]
+        cast_span: Span,
+        cast_ty: Ty<'tcx>,
+    },
+    #[suggestion(hir_typeck_suggestion, code = ".addr()", applicability = "maybe-incorrect")]
+    Other {
+        #[primary_span]
+        cast_span: Span,
+    },
+}
+
 #[derive(Subdiagnostic)]
 pub enum HelpUseLatestEdition {
     #[help(hir_typeck_help_set_edition_cargo)]